1. FIELD OF THE INVENTION
This invention relates to an improvement in a disposable delivery system that provides a continuous flow of fluid to a patient. This invention also relates to a simplified method for physiological blood pressure monitoring and eliminating the need for Heparin in "Heparin Lock" devices.
2. DESCRIPTION OF THE PRIOR ART
Many infusion systems have been proposed and sold for the dispensing of drugs into a patient. With few exceptions, these systems contain both reusable (hardware components) and disposable parts. These systems include, for the most part, electrical components, with their attendant costs and limitations. The system as shown and described in the present application has an infusion delivery system that does not use or utilize electrical or electronically-related components, and this delivery system is completely disposable after a one-time use.
The delivery of medication may include a catheter as the vascular access device or dispensing may be through a needle penetrating an implanted vascular access port which in turn is connected to a blood vessel using an internal catheter. The delivery system of this medication includes a fluid reservoir. Fluid delivery is continuous for an extended and determined period of time. Devices of this type are preferably light in weight and pocket accessible. A termination of use occurs when the medical procedure is completed. The device is then simply discarded. At present, most, if not all, disposable ambulatory medicator infusion devices employ an elastomeric bladder which is caused to be expanded as the drug is fed or otherwise flows into the bladder. The delivery is dependent upon the capability of the bladder to expand and contract. For example, U.S. Pat. No. 3,486,539 describes a structure employing a bladder as a means of storage as well as contraction to provide for expulsion of fluid while providing pressure. Such a dispensing device anticipates filling a bladder through a front-connected needle with a flow metering restrictor. U.S. Pat No. 3,993,069 describes a system having an expansible elastomeric bladder and a separate flow-control device and outer flow restrictor. U.S. Pat. No. 4,318,400 describes an elastomeric bladder-powered infuser and a tubular cas enclosure to prevent excessive expansion of the bladder. Drugs are fed through a needle and syringe to the bladder through a resilient plug at the rear of the device . U.S. Pat. No. 4,386,929 describes a structure similar to that of U.S. Pat. No. 4,318,400.
U.S. Pat. No. 4,419,096 describes an apparatus of similar construction as above with an added lumen and bulbar filler portions to establish the contracted shape of the elastomeric bladder when the contents are, or substantially are, expelled.
In the disclosure to be hereinafter more fully described, the delivery of fluid to a catheter may include a flow-stopping device. The fluid flow may be used with a pressure transducer to produce waveforms of blood pressure, with electrical signals from the pressure transducer sent to a display and monitor. In another arrangement, medication (drugs) may be injected using a Y-block arrangement downstream of the pressure piston. The piston as carried in a housing may be advanced by external means.